Process to prepare novel antibiotic compounds

ABSTRACT

A process is provided which yields derivatives of cephalosporins and penicillins. The process starts with 7-acylaminocephalosporin, or 6-acylaminopenicillin, then the latter compounds are treated with an organolithium compound, followed with t-butyl-hypochlorite. Finally, a defined reagent is added yielding a side chain on the carbon adjacent to the amino-nitrogen. Novel intermediate compounds are also described. The end compounds prepared are active against both gram-positive and gram-negative bacteria.

RELATIONSHIP TO OTHER APPLICATIONS:

This is a continuation of application Ser. No. 615,856, filed Sept. 23,1975, now U.S. Pat. No. 4,041,029, issued Aug. 9, 1977, which in turn isa division of Ser. No. 340,803, filed Mar. 13, 1973, now abandoned,which in turn is a continuation-in-part of Ser. No. 203,056, filed Nov.29, 1971, now abandoned.

This invention relates to a new process for preparing compounds knownchemically as 7-acylaminocephalosporanic acid derivatives havingsubstituents at position-7. This process is also useful in preparing theanalogous 6-substituted compounds in the penicillin series.

The compounds prepared by the process of this invention are thefollowing - (the numbers indicate ring position): ##STR1## and ##STR2##wherein R₁ is loweralkoxy, loweralkanoyloxy, cyano, or hydroxy; X ishydrogen, amino, or carboxyl; R is phenyl or a 5-membered heterocyclicring having 1-2 hetero atoms, the latter being either S, O, or N; A ishydrogen, loweralkanoyloxy, carbamoyloxy, thiocarbamoyloxy,N-loweralkylcarbamoyloxy, N-loweralkylthiocarbamoyloxy,N,N-diloweralkylcarbamoyloxy, N,N-diloweralkylthiocarbamoyloxy,pyridinium, alkylpyridinium, halopyridinium, or aminopyridinium; and Mis sodium, potassium, benzyl, benzhydryl, trimethylsilyl,trichloroethyl, methoxymethyl, hydrogen, benzoylmethyl, ormethoxybenzyl.

By the phrase "5-membered heterocyclic ring having 1-2 heteroatoms, thelatter being either S, O, or N" is meant any of those 5-membered cyclicorganic structures, saturated or unsaturated, which have sulfur, oxygen,or nitrogen in 1 or 2 positions in the ring. It is meant to includewithin this definition, mono- or di-aza, mono- or di-oxa, or mono- ordi-thio ring structures, as well as rings having mixed hetero atoms.Hetero rings which are included within this definition are isoxazole,oxazole, isothiazole, thiazole, pyrazole, 3H-pyrazole, 4H-pyrazole,imidazole, 2H-imidazole, 4H-imidazole, 3H-1,2-oxathiole,1,2-oxathiolane, 5H-1,2-oxathiole, 1,3-oxathiole, 1,2-dioxole,1,3-dioxole, 1,3-dioxolane, 3H-1,2-dithiole, 1,2-dithiolane,1,3-dithiole, 1,3-dithiolane, pyrrole, pyrroline, pyrrolidine,2H-pyrrole, 3H-pyrrole, furan, or tetrahydrofuran, etc. It is understoodthat the point of attachment of these rings to the rest of the moleculecan be in any suitable position of the ring.

It is noted that when X is amino or carboxyl, it can be blocked forprotection during the series of reactions described herein, then theblocking group removed subsequently as desired.

The nomenclature used in this application is further defined as follows:The compound, ##STR3## is called 7-aminocephalosporanic acid. The sidechain at 3 is inherently contained in the name. By comparison, theskeleton ##STR4## is called 7-aminodecephalosporanic acid. Derivativesof this compound which have substituents at 3- are named7-amino-3-R-decephalosporanic acid.

In the above structural formulas, Compound I is 7-acylamino-7-R₁ -3-CH₂A-decephalosporanic acid, and Compound II is a 6-acylamino-6-R₁-penicillanic acid.

In summary, this invention provides a route for substituting the desiredR₁ group at position 7- (or 6-) of the desired cephalosporin (orpenicillin).

The starting materials useful in this process are the following:##STR5## wherein R, and X are as defined above, and M' is benzyl,benzhydryl, trimethylsilyl, trichloroethyl, methoxymethyl,benzoylmethyl, or methoxybenzyl, and "--Z--" is used in Formula III torepresent either the group ##STR6## respectively, representing thepenicillin or the cephalosporin structures. A is as defined above. Theuse of Z is appropriate since any of a great number of substituents candepend from that part of the ring, in both the penicillin and thecephalosporin series. The inventive process of this invention, involvingas it does the carbon adjacent to the amino group, is not affected bythe substituent at Z. One can readily see that the exemplarysubstituents of this application are illustrative only of preferredembodiments and that many other substituents can be employed.

These starting materials are prepared by acylating the desiredcephalosporin or penicillin having a free 7- (or 6-) amino group. Theacylating agent is a substituted acetic acid halide or anhydride; mostsuitably a substituted acetic acid chloride having the formula: ##STR7##The free amino-containing compound and the acylating agent are mixedtogether in approximately equimolar amounts in an inert solvent. Thereaction proceeds spontaneously and quickly, being completed within afew hours. The 7-acylaminocephalosporin or 6-acylaminopenicillin (III)is then recovered and purified using standard procedures.

The starting material III is then treated in a sequence of reactions toyield an acyl imine intermediate. The sequence of reactions aredescribed as preferably occurring in one reaction vessel; however, itmay be desirable to isolate or conduct the reaction in differentvessels; this modification is deemed within the skill of thepractitioner.

Preferably, the starting material is first dissolved in an inertsolvent. Any solvent which does not hinder the further reactions ispractical, common operable solvents including methylene chloride ortetrahydrofuran. However, the presence of the solvent or its identity isnot critical to the reaction.

The starting material is then cooled to a low temperature. This is acritical step in the reaction. Preferably, the temperature to which itis cooled is below -60° C.; most preferably, it is between -100° C. and-50° C. It is also useful to introduce an inert atmosphere to thereaction vessel at this point to minimize undesirable side reactions;nitrogen or one of the inert gases, such as argon, helium, etc., wouldbe suitable.

Once the starting material is at the low temperature, it is admixed withabout an equivalent of an organolithium compound which had previouslyalso been brought to the low temperature. The identity of theorganolithium compound is not critical, although, as it will beapparent, certain organolithiums are more desirable to increase yieldand minimize side reactions. Specifically, aryllithiums, such asphenyllithium or tolyllithium or other substituted phenyllithiums can beused. Alkyllithiums, wherein alkyl can be straight or branched having1-6 carbon atoms, are also useful, such as methyllithium ort-butyllithium. Lithium alkylamides or dialkylamides wherein alkyl iseither straight or branched having 1-6 carbon atoms, e.g., lithiumdiisopropylamide, are also useful.

The organolithium is either added to the starting material or viceversa. The organolithium, particularly the lithiumamides, can also beprepared in situ, i.e., by dissolving, e.g., methyllithium, then adding,e.g., diisopropylamine, stirring, and adding the starting material.

It will be clear from the above discussion that about a stoichiometricor equivalent amount of some organic lithium base is necessary. Theexact chemical identity of the organolithium is not critical.

As has been stated, the temperature of both the starting material andthe organolithium are below -20° C. preferably -100° C. to -50° C. Theaddition of the two is completed within a relatively short period oftime. Following the addition, while the temperature is kept within thedesirable temperature range, an excess, and preferably from about 1-3equivalents, of an active halogen transfer agent is added. Preferably,an active chlorine or bromine transfer agent is used, but the otherhalogens are operable. By the term "an active halogen transfer agent" ismeant a chemical compound having a halogen attached to a carbon orhetero atom of the chemical compound and having electrochemical bondstrengths within the compound such that the hetero atom portion of thecompound can easily form an anion. Besides a hetero atom, a carbon atomfragment can also serve as the anion portion, if it has anion stabilizergroups attached. Examples of such compounds can be readily supplied bythose skilled in the art; for instance, commonly used compounds includeN-chloroacetamide, N-bromoacetamide, N-chlorosuccinimide,N-bromosuccinimide, t-butyl hypobromite, t-butyl hypochlorite,N-chlorosulfonamide, N-bromosulfonamide, α-chloromalonic esters andvarious derivatives of these compounds, such asN-chloro(substituted)sulfonamides, etc.

The halogen transfer agent is preferably lowered in temperature to thereaction range before addition.

Following addition of the halogen transfer agent, there is an optional"rest period" for the reaction. The mixture is permitted to rest for1-15 minutes, and then optionally brought to a warmer temperature, fromabout -30° C. to 0° C., preferably -20° C. to -10° C. Although we preferto conduct the next step at the higher temperature, it is not essential;the entire reaction can be conducted below -40° C.

The purpose for the "rest period", although it is not critical to thereaction, is to allow the various components in the reaction mixture toreact to yield the desired intermediate acylimine compound: ##STR8##wherein R, X, M', and Z are as defined.

Although we are not completely sure of the mechanics of this reactionand do not wish to be bound by theory, it appears that generally areactant is formed in situ during the reaction which can be termed a"strong hindered base". By this phrase is meant a strong base which canreact with the halogen supplied by the halogen transfer agent but whichwill not subsequently participate in any undesirable side-reactions,especially with the relatively fragile β-lactam ring. For example, whenthe halogen transfer agent is t-butyl hypochlorite, the strong hinderedbase formed is lithium t-butoxide. In turn, this ultimately yieldslithium chloride and t-butanol. The latter does not react with theβ-lactam since the alcohol is strongly hindered by the three methylgroups around it.

Obviously, the identity of the "strong hindered base" depends upon theidentity of the halogen transfer agent. We have found that in any caseit is desirable to add about an additional equivalent of lithiumt-butoxide or a similar hindered base in addition to that formed insitu. For example, suitable hindered bases include diazabicyclononane(DBN), diazabicycloundecane (DBU), di-t-butyl-potassium-phenoxide,1,8-bis(dimethylamino)-naphthalene, N-lithiosuccinimide, etc. Theadditional amount of the hindered base is added before the mixture iswarmed to the higher temperature range, i.e., -30° C. and above.

Once the reaction mixture is at the higher temperature range, allreactants having been added, the reagent capable of adding onto thedesired 7α(or 6α) position of the cephalosporin or penicillin is added.The specific choice of reagent depends upon the desired group atposition 7- (or 6-) of the cephalosporin or penicillin. Methanol isemployed when a methoxy group is desired; water is used to prepare ahydroxy substituent; and hydrogen cyanide is used to prepare a cyanosubstituent. Obviously, the loweralkoxy or loweralkanoyloxy groups canbe prepared using the lower alkanol or lower alkanoic acids as reagents.Other useful reagents include hydrazoic acid, to yield an azido group;hydrogen sulfide, to yield a mercapto group; any hydrohalic acid, suchas hydrogen chloride, hydrogen fluoride, or hydrogen bromide, to yieldthe chloro, fluoro, or bromo groups, respectively; or a loweralkylmercaptan, such as methyl mercaptan, to yield loweralkylthio,especially methylthio.

These reagents can all be described by the formula

    R.sub.1 H                                                  VI

wherein R₁ is hydroxy, mercapto, formyloxy, loweralkanoyloxy, loweralkoxy, loweralkylthio, azido, fluoro, chloro, bromo, or cyano.

Besides the reagents being employed as the free acids, they can also beused as anions in a tertiary amine salt. Suitable tertiary amine cationsinclude triloweralkyl ammonium, wherein alkyl can be the same ordifferent and has 1-6 carbon atoms, such as triethylammonium, andpyridinium. As typical examples of useful salts, are included:triethylammonium formate, pyridinium sulfide, triethylammonium chloride,and the like. The tertiary amine salts can be easily prepared and usedin the reaction as described below.

The chosen reagent is employed in approximately equimolecular amounts,although a molecular excess can be used successfully. The mixture isthen permitted to react, while stirring if desired, for from 5-60minutes, and the temperature allowed to rise to ambient temperature. Thereaction is then quenched by the addition of a solvent such as benzene,which contains a small amount of acetic acid. The solution is thenwashed and worked up using conventional procedures to recover thedesired end products I or II.

The compounds prepared by the process of this invention are useful asantibacterial agents against both gram-positive and gram-negativebacteria. In addition, resistance to β-lactamases has been demonstrated.The activity spectrum includes effectiveness against many bacteria,including in vivo on Proteus morganii, and, in addition, against E.coli, P. vulgaris, P. mirabilis, S. schottmuelleri, K. pneumoniae AD, K.pneumoniae B, and P. arizoniae.

In addition to the specific end product as defined in structural formulaI, other compounds which are active antibacterials can also be preparedusing the process described herein. The compounds which can be preparedhave the following structural formula: ##STR9## It is noted that theanalogous Δ² compounds which can also be prepared using the processesdescribed herein are valuable intermediate compounds because of theirgreater acid stability, and can be converted to Δ³ compounds easily. Thevarious substituents have the following meanings: X is hydrogen, halo,amino, guanidino, phosphono, hydroxy, tetrazolyl, carboxyl, sulfo, orsulfamino;

R is phenyl, substituted phenyl, a monocyclic heterocyclic 5- or6-membered ring containing one or more oxygen, sulfur, or nitrogen atomsin the ring, substituted heterocycles, phenylthio, heterocyclic, orsubstituted heterocyclic thio-groups, or cyano; the substituents on theR group being halo, carboxymethyl, guanidino, guanidinomethyl,carboxamidomethyl, aminomethyl, nitro, methoxy, or methyl;

A is hydrogen, hydroxy, halo, mercapto, cyano, alkanoyloxy,alkanoylthio, aroyloxy, aroylthio, heteroaryloxy or heteroarylthio, thehetero ring having 5-6 members and having 1-3 hetero atoms, being O, S,or N or combinations thereof, azido, amino, carbamoyloxy, alkoxy,alkylthio, carbamoylthio, thiocarbamoyloxy, benzoyloxy,(p-chlorobenzoyl)oxy, (p-methylbenzoyl)oxy, pivaloyloxy,(1-adamantyl)carboxy, substituted amino such as alkylamino,dialkylamino, alkanoylamino, carbamoylamino, N-(2-chloroethylamino),5-cyano-triazol-1-yl, 4-methoxycarbonyl-triazol-1-yl, or quaternaryammonium such as pyridinium, 3-methylpyridinium, 4-methylpyridinium,3-chloropyridinium, 3-bromopyridinium, 3-iodopyridinium,4-carbamoylpyridinium, 4-(N-hydroxymethylcarbamoyl)pyridinium,4-(N-carbomethoxycarbamoyl)pyridinium, 4-(N-cyanocarbamoyl)pyridinium,4-(carboxymethyl)pyridinium, 4-(hydroxymethyl)pyridinium,4-(trifluoromethyl)pyridinium, quinolinium, picolinium, or lutidinium;N-loweralkylcarbamoyloxy, N,N-diloweralkylthiocarbamoyloxy,alkanoylcarbamoyloxy, hydroxyphenyl, sulfamoyloxy, alkylsulfonyloxy, or(cis-1,2-epoxypropyl)phosphono;

and M is an alkali metal, benzyl, alkanoyloxymethyl, alkylsilyl,phenalkanoyl, benzhydryl, alkoxyalkyl, alkenyl, trichloroethyl,hydrogen, benzoylmethyl, or methoxybenzyl.

Preferably in the compounds of Formula V, X is hydrogen, amino orcarboxyl, R is phenyl, or a 5-6 membered heterocyclic ring having 1-2hetero atoms, the latter being either S, O, or N;

A is hydrogen, halo, azido, cyano, hydroxy, alkoxy, carbamoyloxy,thiocarbamoyloxy, N-loweralkylcarbamoyloxy,N,N-diloweralkylcarbamoyloxy, N-loweralkylthiocarbamoyloxy,N,N-diloweralkylthiocarbamoyloxy, alkanoyloxy, aroyloxy, mercapto,alkylthio, amino, alkylamino, alkanoylamino, hydroxyphenyl,sulfamoyloxy, quaternary ammonium, alkylsulfonyloxy, or(cis-1,2-epoxypropyl)phosphono;

and M is alkali metal, benzyl, alkylsilyl, phenalkanoyl, alkoxyalkyl,pivaloyloxymethyl, alkenyl, trichloroethyl, hydrogen, benzoylmethyl, ormethoxybenzyl.

Even more preferably, X is hydrogen, amino, or carboxyl; R is phenyl ora 5-membered heterocyclic ring having 1-2 hetero atoms, the latter beingeither S, O, or N;

A is hydrogen, loweralkanoyloxy, heteroarylthio, carbamoyloxy,thiocarbamoyloxy, N-loweralkylcarbamoyloxy,N-loweralkylthiocarbamoyloxy, N,N-diloweralkylthiocarbamoyloxy,pyridinium, alkylpyridinium, halopyridinium, or aminopyridinium; and

M is sodium, potassium, benzyl, benzhydryl, trimethylsilyl,trichloroethyl, methoxymethyl, hydrogen, benzoylmethyl, ormethoxybenzyl.

Still more preferably, X is hydrogen or carboxyl;

R is phenyl, or a 5-membered heterocyclic ring having one O or one Shetero atom;

A is hydrogen, loweralkanoyloxy, carbamoyloxy, N-loweralkylcarbamoyloxy,N,N-diloweralkylcarbamoyloxy, pyridinium, alkylpyridinium,halopyridinium, or aminopyridinium;

And M is sodium, potassium, benzhydryl, methoxymethyl or hydrogen.

Most preferably, X is hydrogen or carboxyl;

R is phenyl, thienyl, or furyl;

A is hydrogen, loweralkanoyloxy, carbamoyloxy, or pyridinium; and

M is sodium, potassium, benzhydryl, methoxymethyl, or hydrogen.

In addition, compounds of Formula VII above wherein the sulfur atom ispresent as the sulfoxide ##STR10## can be prepared in this inventivereaction. It will also be apparent that the process described herein canalso be used to prepare analogous compounds in the penicillin series;##STR11## wherein R, R₁, M, X, and A are the same as defined in FormulaVII.

The compounds of Formula VII can generally be prepared from 7-ACA orknown derivatives thereof using the general process outlined in thepreparative examples.

The blocking group on the acid functionality at position-4 of thecephalosporin ring (or position-3 of the penicillin) can be removedfollowing any of the reactions of this invention. The removal can beaccomplished using methods available to those in the art.

The penicillins of Formula VIII can be prepared from 6-APA or knownderivatives thereof using procedures analogous to those described forthe cephalosporins.

Other starting materials useful in the application of these inventivereactions can be prepared in accordance with known methods, see, e.g.,Belgium Pat. No. 650,444 or U.S. Pat. No. 3,117,126, or using thefollowing preparations.

The term "loweralkyl" is employed to mean a carbon chain having 1-6carbon atoms; when more than one loweralkyl group appears in asubstituent, the groups can be the same or different. "Lower alkanoyl"means having 1-6 carbon atoms.

PREPARATION 1 3-Hydroxymethyl-7-Aminodecephalosporanic Acid

The 3-hydroxymethyl-7-aminodecephalosporanic acid is obtained as thelactone by acid hydrolysis of cephalosporin C in accordance withprocedures known in this art.

PREPARATION 2 3-Pyridiniummethyl-7-Aminodecephalosporanic Acid

This compound is prepared by treating cephalosporin C with pyridinefollowed by acid hydrolysis as described in U.S. Pat. No. 3,117,126.

PREPARATION 3 3-Methyl-7-Aminodecephalosporanic Acid

This compound is prepared from cephalosporin C by catalytic reductionfollowed by hydrolytic removal of the 5-aminodipoyl side chain asdescribed in U.S. Pat. No. 3,129,224.

PREPARATION 4 3-Chloromethyl-7-Aminodecephalosporanic Acid

This compound is prepared from the 3-methyl compound by reaction withchlorine gas. The bromomethyl or iodomethyl derivatives can be preparedfrom the 3-hydroxymethyl compound by reaction with phosphorus tribromideor phosphorus triiodide, respectively.

The starting materials used in the preparation of the compounds ofFormula I can be prepared as follows:

PREPARATION 5 3-Carbamoyloxymethyl-7-Aminodecephalosporanic Acid

7-Aminocephalosporanic acid is treated with 5-butoxycarbonylazide toproduce the 7β-(t-butoxycarbonyl) derivative in accordance with knownmethods. This derivative is then intimately contacted with citrusacetylesterase in aqueous phosphate buffer at pH 6.5-7 for 15 hours and3-hydroxymethyl 7β-(t-butoxycarbonyl)aminodecephalosporanic acid isrecovered from the resulting reaction mixture.

To 0.2 g. of 3-hydroxymethyl 7β-(t-butoxycarbonyl)aminodecephalosporanicacid suspended in 5 ml. of acetonitrile, cooled to 0° C. and maintainedunder nitrogen atmosphere is added 0.15 ml. of chlorosulfonylisocyanate. The reaction mixture is stirred for 70 minutes and thenevaporated under diminished pressure to dryness. The resulting residueis taken up in 10 ml. of ethylacetate and 10 ml. of 0.1 N phosphatebuffer. The pH of the aqueous layer is adjusted to about 1.6 and themixture stirred for 21/2 hours at room temperature. The pH is thenadjusted to about 8 with aqueous tripotassium phosphate solution, andthe aqueous phase is separated. The organic phase is re-extracted with10 ml. of phosphate buffer at pH 8. The combined aqueous phase isadjusted to pH 2.1 with hydrochloric acid and extracted twice withethylacetate. The ethylacetate extractions are dried over sodium sulfateand evaporated under diminished pressure to afford 0.055 g. of residue.This residue is washed with ether to afford3-carbamoyloxymethyl-7β-(t-butoxycarbonyl)-aminodecephalosporanic acidwhich is recovered as a yellow solid.

3-Carbamoyloxymethyl-7β-(t-butoxycarbonyl)-aminodecephalosporanic acid(0.5 g.) in 3.5 ml. of anisole is stirred with 2 ml. of trifluoroaceticacid at 0° C. for 5 minutes. The resulting reaction mixture isevaporated under reduced pressure to afford3-carbamoyloxymethyl-7-aminodecephalosporanic acid which is purifiedfurther by crystallization from ethylacetate.

PREPARATION 6 Trimethylsilyl3-Carbamoyloxymethyl-7-Aminodecephalosporanate

A mixture of 0.5 g. of 3-carbamoyloxymethyl-7-aminodecephalosporanicacid, 2 ml. of hexamethyldisilazane and 8 ml. of chloroform is stirredovernight at reflux temperature protected from moisture. The solvent andexcess hexamethyldisilazane are removed at reduced pressure, leaving aresidue containing trimethylsilyl3-carbamoyloxymethyl-7-aminodecephalosporanate.

PREPARATION 7 Benzhydryl7-(2-Thienylacetamido)-3-Carbamoyloxymethyl-Decephalosporanate A.7-Amino-3-Carbamoyloxymethyldecephalosporanic Acid Benzhydryl Ester

272 Mg. of 7-amino-3-carbamoyloxymethyldecephalosporanic acid isslurried 5 minutes at 25° C. in 7 ml. of dioxane with 170 mg. ofp-toluenesulfonic acid H₂ O. Methanol (2 ml.) is added, the solvents areremoved in vacuo, and dioxane is twice added and evaporated in vacuo.Dioxane (8 ml.) is added, and then 290 mg. of diphenyldiazomethane.After the evolution of nitrogen is complete, the solvent is distilled invacuum, and the residue stirred with methylene chloride (10 ml.) andwater (10 ml.) containing sufficient K₂ HPO₄ to bring the pH to 8. Thelayers are separated and the aqueous portion extracted twice more withCH₂ Cl₂. The combined organic layers are dried with sodium sulfate,filtered and evaporated, leaving oily crystals. Washing with etheraffords a dry solid, 150 mg. (35%), m.p. 110°-115° C. which is theproduct, 7-amino-3-carbamoyloxymethyldecephalosporanic acid benzhydrylester.

In a like manner, the benzhydryl and other esters of3-methyl-7-aminodecephalosporanic acid,3-chloromethyl-7-aminodecephalosporanic acid, and 7-aminocephalosporanicacid can be prepared.

B. Benzhydryl3-Carbamoyloxymethyl-7-(2-Thienylacetamido)-Decephalosporanate

Benzhydryl 7-amino-3-carbamoyloxymethyldecephalosporanate (452 mg.) isreacted with 161 mg. of thienyl acetyl chloride in 25 ml. of methylenechloride containing 0.5 ml of pyridine.

The reaction mixture is held at 0° C. for 15-60 minutes and then raisedto room temperature and held an additional 15-60 minutes. The mixture isthen washed with water, dilute phosphoric acid (buffered to pH 2),water, and dilute sodium bicarbonate. After drying over MgSO₄, thesolution is filtered and evaporated. The crude solid is purified bychromatography on silica gel and eluted using for instance 4:1chloroform:ethyl acetate. The product prepared is the benzhydryl7-(2-thienylacetamido)-3-carbamoyloxymethyldecephalosporanate.

PREPARATION 8 Benzyl 6-(2-Phenylacetamido)-Penicillanate

The benzyl ester of 6-APA is reacted with 2-phenyl acetyl chloride usingthe same reaction conditions as described above. The product, benzyl6-(2-phenylacetamido)penicillanate is recovered and identified.

EXAMPLE 1 Benzyl 6α-Methoxy-6β-(2-Phenylacetamido)-Penicillanate

Benzyl 6-(2-phenylacetamido)-penicillanate (0.25 mmole) in 5 ml. oftetrahydrofuran is cooled to -78° C. under nitrogen. One equivalent(0.109 ml. of 2.3M) phenyl lithium is added followed by 35 microlitersof t-butyl hypochlorite. This mixture is permitted to stand 60 secondswhile the temperature is raised to -17° C., then one ml. methanol isadded to the solution. The mixture is removed from the ice bath andstirred for 5 minutes, then 40 ml. benzene containing 0.1 ml. aceticacid is added. The solution is washed with water containing pH 2phosphate buffer; water, and finally water containing pH 8 phosphatebuffer; dried with MgSO₄, filtered and evaporated to afford 87 mg. crudebenzyl 6α-methoxy-6β-(2-phenylacetamido)-penicillanate. The purecompound, 13 mg., is obtained after purification by chromatography on 5g. silica gel, eluting with 4:1 chloroform/ethyl acetate.

EXAMPLE 2 Benzyl 6α-Hydroxy-6β-(2-Phenylacetamido)-Penicillanate

Benzyl 6β-(2-phenylacetamido)penicillanate, 0.106 g. (0.25 mmole), in 5ml. THF is cooled to -78° C. under nitrogen. One equivalent (0.109 ml.of 2.3M) phenyllithium is added, followed by 0.060 ml. t-butylhypochlorite. After 1 minute at -78° C., a solution of 0.024 ml. oft-butyl alcohol and 0.109 ml. 2.3M phenyllithium in 2 ml. THF is added.The reaction mixture is warmed to -17° C., forming the iminointermediate compound in situ.

To this solution is added 0.1 ml. water in 2 ml. THF at -17° C. Thereaction is stirred 5 minutes out of the ice bath, and then 40 ml. ofbenzene containing 0.1 ml. acetic acid is added. The solution is washedwith water containing pH 2 phosphate buffer, water, and finally watercontaining pH 8 phosphate buffer; dried with MgSO₄ ; filtered andevaporated, affording the crude product. Chromatography on silica gel,eluting with 4:1 CHCl₃ -EtOAc, affords pure benzyl6α-hydroxy-6β-(2-phenylacetamido)penicillanate, 25 mg.

EXAMPLE 3 Benzyl 6α-Cyano-6β-(2-phenylacetamido)Penicillanate

Benzyl 6β-(2-phenylacetamido)penicillanate, 0.106 g., in 5 ml. oftetrahydrofuran is cooled to -78° C. under nitrogen. Phenyllithium,0.109 ml. of 2.3M, is added, followed by 0.060 ml. t-butyl hypochlorite.After 1 minute is added a solution of 0.2 ml. hydrogen cyanide and 0.164ml. of phenyllithium in 2 ml. of tetrahydrofuran. The reaction isallowed to warm to room temperature over 20 minutes, and then worked upas in Example 2 above. Chromatography affords a small amount of benzyl6α-cyano-6β-(2-phenylacetamido)penicillanate, identified by massspectroscopy.

EXAMPLE 4 Benzyl 6β-(2-Phenylacetamido)-6α-Formyloxypenicillanate

Using the same general process described above in Example 2, a solutionof the imino intermediate at -17° C. is treated with 0.075 ml. ofanhydrous formic acid and 0.278 ml. of triethylamine in 4 ml. oftetrahydrofuran. After 5 minutes stirring out of ice, 40 ml. of benzeneis added, and the reaction mixtue washed twice with water. The mixtureis purified as above, yielding 9 mg. ofbenzyl-6β-(2-phenylacetamido)-6α-formyloxypenicillanate.

In the same manner, benzyl 6β-(2-phenylacetamido)-6α-azidopenicillanate,benzyl 6β-(2-phenylacetamido)-6α-chloropenicillanate, benzyl6β-(2-phenylacetamido)-6α-bromopenicillanate, benzyl6β-(2-phenylacetamido-6α-mercaptopenicillanate, or benzyl6β-(2-phenylacetamido)-6α-methyl-thiopenicillanate is preparedrespectively, using hydrazoic acid, hydrochloric acid, hydrobromic acid,hydrogen sulfide, or methylmercaptan.

EXAMPLE 5 Benzhydryl7β-(2-Thienylacetamido)-7α-Methoxy-3-Carbamoyloxymethyldecephalosporanate

Using the same process as described in Example 1, using benzhydryl7β-(2-thienylacetamido)-3-carbamoyloxymethyldecephalosporanate as thestarting material, the product benzhydryl7β-(2-thienylacetamido)-7α-methoxy-3-carbamoyloxymethyldecephalosporanateis prepared. The other cephalosporin derivatives can also be preparedusing processes as described in Examples 2-4.

EXAMPLE 63-Carbamoyloxymethyl-7-Methoxy-7-(2-Thienylacetamido)-DecephalosporanicAcid

Benzhydryl 3-carbamoyloxymethyl-7-(2-thienylacetamido)decephalosporanate(300 mg.) in 0.5 ml. in anisole and 2.5 ml. of trifluoroacetic acid isreacted for 15 minutes at 10° C. The resulting mixture is evaporated atreduced pressure and flushed twice with anisole. The residue isdissolved in methylene chloride and extracted with 5% sodium bicarbonatesolution. The aqueous solution is adjusted to pH 1.8 with 5% phosphoricacid and extracted with ethyl acetate. The organic solution is dried andevaporated to yield the pure3-carbamoyloxymethyl-7-methoxy-7-(2-thienylacetamido)decephalosporanicacid, m.p. 165°-167° C. UV and NMR analysis provide data consistent withthe assigned structure. The benzyl blocking group in the penicillanatescan be removed in the usual manner by reduction over palladium catalyst.

EXAMPLE 7 Sodium3-Carbamoyloxymethyl-7-Methoxy-7-(2-Thienyl-acetamido)-Decephalosporanate

The procedure as in Example 6 is followed, except that the pH isadjusted to 8.0 with dilute sodium hydroxide and concentrated undervacuum to remove the solvents. The mono-sodium salt of3-carbamoyloxymethyl-7-methoxy-7-(2-thienylacetamido)decephalosporanicacid is recovered.

What is claimed is:
 1. The compound ##STR12## wherein R is a phenyl orthienyl or furyl; X is hydrogen, amino, or carboxyl;M' is benzyl,benzhydryl, trimethylsilyl, trichloroethyl, methoxymethyl,benzoylmethyl, or methoxybenzyl.
 2. The compound of Claim 1 in which Xis hydrogen or carboxyl and R is phenyl or thienyl.